Prioritizing transport decarbonization strategies in Nigeria: An intuitionistic fuzzy decision framework for energy transition policy

Nigeria's transport sector is a major and growing source of Greenhouse Gas (GHG) emissions, largely because mobility remains heavily dependent on petroleum products. Efforts to shift toward low-carbon transport are hindered by economic, institutional, infrastructural, and technological constraints. This study develops an integrated decision framework for prioritizing these challenges and identifying suitable policy responses within Nigeria's wider energy transition. Drawing on the literature, national policy documents, and the judgments of six experts from academia, government, transport, and energy, the study evaluates eight decarbonization challenges and five policy alternatives. It proposes an Intuitionistic Fuzzy (IF) extension of the RANking COMparison method (IF-RANCOM) to determine the relative importance of the challenges while considering uncertainty and hesitation in expert judgments. The resulting weights are incorporated into an Intuitionistic Fuzzy Additive Ratio Assessment (IF-ARAS) model to evaluate the policy alternatives. Compromise Fuzzy Ranking (CFR) is then used to reconcile differences among expert assessments and produce a collective ranking. The findings identify Nigeria's economic dependence on petroleum as the most important barrier, followed by weak policy frameworks and planning, inadequate infrastructure and technological capacity, and the high cost of zero-emission vehicles. Promoting mass transit is ranked as the most suitable policy response. Comparative and sensitivity analyses reveal that the main rankings remain stable under different methodological assumptions and parameter settings. The findings demonstrate the need for coordinated investment in mass transit, integrated transport and land use planning, sustainable financing, infrastructure modernization, and institutional reform. The proposed framework may also support other fossil-fuel-dependent developing economies in aligning transport priorities with energy security, social inclusion, and long-term decarbonization goals.